Discovery of deadly ash beetle on Pier, Jackson streets confirms fear that infestation is spreading throughout area

Three more ash trees, these on Pier and Jackson streets in downtown Port Washington, were found to be infested with the emerald ash borer Monday.

That brings the total number of trees in Port known or suspected to be infested with the borer to roughly a dozen. About half were found atop the ravine overlooking the city’s bike path. Others are in Veterans Memorial Park and near the water filtration plant.

“It’s clear it’s here,” Jon Crain, the city’s arborist, said.

With the cluster of cases found in the area, it’s apparent the beetle has been here for years and has likely spread beyond that area, he said.

“I do suspect it’s throughout the city,” Crain said. “Chances are, if we’re finding it down there, it is throughout (the city) and we’re just not seeing it yet.”

That’s because it takes three to five years for the beetle to kill an ash tree. Many of the trees discovered recently are dead.

The drought we’re experiencing now is a cause for concern, Crain added, noting it weakens trees.

The city is now developing a plan to evaluate all its ash trees, Public Works Director Rob Vanden Noven said.

“We will be evaluating them at least once a year and take down the ones showing signs of infestation as quickly as possible,” he said.

The city shouldn’t wait until they’re dead because ash become extremely brittle when they die, Vanden Noven said.

“The Department of Natural Resources said if a dead limb falls onto the sidewalk, it will likely shatter into a million pieces,” he said.

In the ravine and other densely wooded or sloped areas, the city may have to let nature take its course because of the difficulty in getting to them, Vanden Noven said.

Once the infested ash trees are cut down, the city will have to grind the wood into tiny pieces to kill any larvae and insects in it, Crain said. The ash wood chips will be kept separate and won’t be available for public use.

The city already has a map showing the location of 1,100 ash trees planted along the streets, Vanden Noven said. Many streets in relatively new subdivisions have clusters of ash, including Bley Park Estates, Spinnaker West and the southern half of the Lake Ridge development, he said.

Parks and Recreation Director Charlie Imig said his department is doing an inventory of the ash trees found in parks as well.

In Upper Lake Park, which has already been mapped, there are 156 ash trees and 162 other species, Imig said.

Many of those ash are in a dense cluster along the bluff and ravine, Crain said, as well as in the center green space.

Ash trees are so prevalent because they were considered a good tree to plant after Dutch elm disease decimated that species.

“I think the borer is going to be a lot like Dutch elm disease, where ultimately you end up with no ash trees,” Vanden Noven said.

“Ash is a great hardwood tree. It’s a good, durable street tree. They grow to a perfect size to provide a canopy and have a great shape.”

Officials haven’t planted ash trees along streets or in the parks since 2005, after they learned of the devastation caused by the borer in other parts of the country.

“From the photos I’ve seen of communities in Michigan, it’s not pretty,” Vanden Noven said. “If people want to know the value of having a tree in front of their home, they’re going to see it.

“If you live on a street with mostly ash trees, never in your lifetime are you going to see that same canopy over the street.”

The state has been working to find a biological solution to the borer, but it will take years before researchers know whether it is effective in this area.

In the meantime, residents with ash trees on their property generally have two options, officials said.

“If they have a tree that means a lot to them I suggest getting treatment on them fast,” Crain said.

Although not guaranteed, there are chemical treatments that can be used to try to prevent the borer from attacking trees. The most effective of these are injections into the trunk of the tree, Crain said, adding those that are put into the soil around the tree are less efficient.

Residents can also plant other trees now to replace ash trees on their property, Vanden Noven said.

“That way, when the ash tree does need to come down, you have a tree that’s beginning to mature to replace it,” he said. “There are lots of different species of trees, and some can grow quite rapidly.”